Left ventrolateral prefrontal cortical activity during reward expectancy predicts mania risk up to one year post scan

Abstract

Introduction: Identification of neural markers associated with risk for manic symptoms is an important challenge for neuropsychiatric research. Previous work has highlighted the association between predisposition for mania/hypomania and elevated reward sensitivity. Elevated activity in the left ventrolateral prefrontal cortex (L vlPFC) during reward expectancy (RE) is associated with measures predictive of risk for manic/hypomanic symptoms. However, no studies have examined this relationship longitudinally. The goal of this study was to identify a neural marker associated with longitudinal risk for manic/hypomanic symptoms.

Methods: We used a card guessing functional magnetic resonance imaging (fMRI) paradigm to examine RE-related L vlPFC activity. One hundred and three young adults who were either healthy or experiencing psychological distress completed a single baseline fMRI scan and self-report measures of manic/hypomanic symptoms. Self-report measures were repeated up to two follow up visits over one year.

Results: We identified a significant positive relationship between baseline RE-related L vlPFC activity and MOODS Manic Domain scores up to one-year post scan. This relationship was specific to manic symptoms and was not present for MOODS depression-related domains.

Limitations: This study was not designed to predict conversion to bipolar disorder, but rather the more proximal construct of lifetime risk for mania/hypomania.

Conclusions: RE-related L vlPFC activity may serve as an important marker of risk for future manic/hypomanic symptoms and may also be a potential target for intervention.

Keywords: Bipolar disorder; Bipolar disorder risk; Left ventrolateral prefrontal cortex; Mania; Reward expectancy; Reward sensitivity.